It was on August 22nd 1988 that Mary Holton was told there was a chance she was expecting conjoined twins.

Two days later, she held her newborn babies, Katie and Eilish, closely in her arms.

They were born with separate heads and necks.

Their bodies were joined from the shoulders down.

Unlike the Manchester twins, who share one heart and one set of Lungs- a fact that has ruled out the survival of one of them- the hultan twins had individual hearts and lungs, giving them a normal life expectancy.

Although their internal organs were fused at the pelvis, their shared liver would be large enough to sustain both of their young lives.

As babies, they were extremely contented.

Eilish was always the quieter of the two, depending on her livelier, more extrovert sister.

To get things done, she had a bigger appetite than Katie, but unusually, Katie was always the plumper of the two.

Together they co-existed in their unique world, but the older they got, the less comfortable it became.

From the start, separation had been a consideration, and as they grew into toddlers, the reality of the future they would share if they stayed together grew more daunting for their parents.

They never learned to walk as a pair and the likelihood was that they never would by the age of three, getting from a to b involved a bum shuffle across the floor.

In time they would be confined to a wheelchair.

After three long years of agonizing, Mary and Liam finally decided to go ahead with surgery.

The chances of a successful separation were good as high as 70 percent.

Their parents in the medical team at Great Ormond Street Hospital, who performed the operation under pediatric Surgeon Professor Louis Spitz, had every reason to hope that the pair would enjoy healthy, independent lives in the future.

With the aid of two velcro dolls, which they stuck together and eased apart, they tried to explain to their three-year-old daughters what the operation hoped to achieve.

If anything, it was Katie who grasped the idea of separation more than her sister.

She would tell little stories about what she would do if they were apart.

But eilish didn’t really seem to take much notice.

And then, on an early spring day in 1992, the operation was carried out.

It took the best part of 24 hours and was pronounced a success, but four days later, for no apparent reason, the monitors attached to Eilish’s heavily sedated body began to behave erratically.

Doctors later put it down to the fact that she had reacted in sympathy with her little sister who was dying beside her.

She had suffered a coronary arrest.

CORONARY ARREST

For almost four weeks, Mary and Liam watched their surviving daughter toss and turn in her bed in intensive care.

The massive wound which had been left on her frail body, where she was joined to her sister, bore the severity of a third degree burn.

Apart from the sheer physical pain left in the aftermath of the surgery, emotionally she seemed drained for a long time.

Afterwards she turned into herself and did not want to speak.

When her parents gently broke at her that Katie had gone to Heaven, it was clear they were telling her something she already knew.